Rough idle, no boost, and CEL - 01 1.8t
 

I have a '01 A4 1.8t and I let my brother barrow the car for a while. After a year I went to pick the car up and the CEL is on, it idles extremely rough(surging idle) and has no boost.

I had the codes pulled, it had the following:

P0237
P0118
P0106
P1425
P1117
P1435
P1421
P1289
P1473
P1500
p0102

I had another MAF that was NIB so I swapped that and it made no difference what so ever. I reset the codes and the car will through those same codes almost instantly.

I have replaced the MAF (as stated) as well as check in the intake and I/C piping for cracks/leaks.

Any other help would be grateful before I just push this thing into the lake out of rage.

codes are for

map sensor P0237

engine coolant temp sensor circuit high P0118

P0106 - Manifold Abs.Pressure or Bar.Pressure Range/Performance

P1425 - Tank Vent Valve Short to Ground

P1117 ????

p1435-Secondary air injection (AIR) pump relay - short to ground


From a quick check on a few of the codes it defiantly looks to be an electrical issue...maybe a bad ecu??? (Just a shot in the dark) But it seems to fit based on the chances of all those different sensors going bad at the same time...not very likely. I'd give it a good once over and start with the basics Check/change fluids, pull the plugs and check them out, maybe seafoam it, check the air filter, check the new maf....I had a maf go out and it sounds like it could be bad...mine had very similar symptoms. It goes into a limp mod and cuts all boost, retards timing, and runs rough and rich.

I swapped the MAF at the local store and still nothing different there.

As for the computer I sourced one that looks like it should be the same as I need. Is anything else needed before swapping them out?

I have checked the everything over the best I can and other then the different headlights I don't see anything that was really messed with to much. I'm taking off the I/C pipping and intake and such to ensure I get a good look at it all as well during this week. Figured at that point I will have more room to check everything on the passenger side since I will have everything removed.

Does it accelerate very bad? Does it have a hard time going over 40? with the rough idling and all that if this is the case then id say it needs a Throtle Body Adaptation. The car does this on its own when you first turn the key but cars have issues and this could be the case. All the methods of performing a throttle body adaptation you read online are garbage and wont work. YOU NEED A VAG COM to do a throttle body adaptation. My car out of nowhere one day was idling extremely rough, misfiring, rpm gauge jumping randomly it was hard to accelerate and it wouldnt go over 40 mph. I did all the methods of doing a throttle body adaption i read online like turning the key waiting pushing the brake and all those methods that didnt work. I got ahold of a vag com and within 15 seconds the car was running better than ever. If you cant figure out your issue look into doing a Throttle Body Adaptation a Vag Com is the only way to fix it if the car isnt doing it by itself.

I thought it might have been my MAF or my cam shaft position sensor or my ECU. I also thought my car was done for but it turned out to be a simple fix. Before digging into your engine to much look at the symptoms for needing a Throtle Body Adaptation and do know that the only way to fix it is with a Vag Com. There are threads on this forum of guys who have Vag Coms that are willing to share.

It revs ok some times other times it has a limiter around 4kish. It is a pain to even move around do to having to rev a little higher or slip the clutch more in order to get it going.

I checked the ECU and has a 4B0 906 018 BG, but for some reason that does not seem correct. I'm going to try and search around here and see if it even has the right computer.

If not, I would think the current PC was never setup for this car so this may have just taken a turn for the worse.

I put the car back together a little and got it started. It still surges and has the same codes. However, with the the ability to see around the turbo a bit more I can see oil is leaking from the turbo. The intake side spins with no shaft play, but I'm wondering if the turbo may be bad

I found this today while looking over the car.

Looks like the MAF wiring was cut for some reason

I also found these two connections not hooked up to anything and could not find a location of where they went.

Definitely fix those MAF wires.

Those two loose connections are not important, but it would be a good idea to reconnect them. One is for the horn, the other is for the fog light. Seems like someone did a number on the car's electronics.